This invention relates generally to improving performance of disc drive actuators and their accompanying servo systems. More particularly, the present invention relates to a damping device that reduces vibrations between a plurality of elongated head arms thereby facilitating an improved head arm seek response and improving the overall drive performance.
A primary function of a disc drive actuator and its accompanying servo control system is to keep the read/write heads on track. Mechanical resonances within the actuator limit the precision of the tracking system and adversely effect the time required for the heads to settle after a seek. Many actuators, and most notably rotary actuators, have relatively long and flexible head arms. Such elongated head arms tend to have separate modes of vibration which are easily excited during normal operation of the disc drive. When such vibrations go undamped or are only lightly damped, they limit the overall performance of the disc drive. In the past, such control problems were typically overcome by limiting the bandwidth of the control system to movements that are not likely to excite such resonances. However, when relatively elongated head arms are used, merely limiting the performance of the control system will have an adverse effect on the overall drive performance.
Prior art attempts to align and support the heads have included efforts that placed inelastic spacer between each pair of adjacent head arms. The spacers and head arms are then joined together using a nut and bolt combination. However, such a system has several real disadvantages. To begin with, the spacers must be precision parts to prevent bending the head arms. Additionally, the removal of any one head arm requires the disassembly of the entire clamping device, including all spacers, and the nut and bolt combination. This drawback is amplified by the fact that such an alignment system is relatively difficult to assemble and disassemble. Further, the vibrations generated by such a device are lightly damped and produce large amounts of motion at resonance.